The present invention relates to a semiconductor laser apparatus usable in apparatuses such as optical pickup apparatuses that read data recorded on an optical recording medium, and to an optical pickup apparatus using the same.
An optical pickup apparatus used in optical memory apparatuses such as CD-ROM and MD (Mini-Disk) for reading a signal of optical disks uses a semiconductor laser apparatus with a semiconductor laser device, a signal detection light receiving device, a hologram device and the like stored in one package. In such a semiconductor laser apparatus, a light beam is emitted from the semiconductor laser device, and then the light beam reflected and returned by an optical disk is diffracted by the hologram device and led to the signal detection light receiving device disposed in a position away from an optical axis of the semiconductor laser device. Such a method is called a hologram laser method.
Examples of a conventional semiconductor laser apparatus using the hologram laser method include one disclosed in Japanese Patent Laid-Open Publication HEI No. 6-5990. The outlined structure thereof is shown in FIGS. 7A and 7B. It is noted that FIG. 7A is an exploded perspective view and FIG. 7B is a perspective outview.
In this structure, a semiconductor laser device (LD) 210 and a signal detection light receiving device 211 are mounted on a stem 201, and a cap 202 is placed so as to cover the LD 210, the signal detection light receiving device 211 and the like, and further on top of the cap 202, a hologram device 203 is mounted. Power supply to internal devices (including the LD 210 and the signal detection light receiving device 211) and signal extraction to the outside are carried out via a lead 208. The package has a circular shape whose upper and lower circular arcs are removed. This shape fulfils a thinner package.
However, the above prior art has following problems.
First, the above-structured package needs the step of forming holes for the leads 208 to go through the stem 201, inserting the leads to the holes one by one, and sealing the holes with an insulating material 209, which brings about such disadvantage as a complicated manufacturing method and a higher cost.
Also, as shown in FIG. 7A, the LD 210 and the signal detection light receiving device 211 are disposed at an angle of 90 degrees from each other, so that mounting of the LD 210 on the stem 201 is different from mounting the light receiving device 211 in that the whole package is required to be inclined 90 degrees for mounting the LD 210. Consequently, in the step of mounting each device, there have been a problem in terms of processing efficiency as well as a problem of an apparatus becoming complicated.
Further, an electrode 212 of the LD 210 shown in FIG. 7A is disposed in the state of being inclined 90 degrees from an electrode 213 of the signal detection light receiving device 211. For wire-boding the LD 210 and the lead 208, therefore, the whole package needs to be rotated 90 degrees first. Consequently, in the step of wire-bonding each device for establishing connection of each other, there have been a problem that work efficiency of wire-bonding is degraded, as well as a problem in terms of reliability and processing efficiency.
As described above, the prior art structure needs the step of forming holes for the leads to go through the stem, inserting the leads to the holes one by one, and sealing the holes with an insulating material, which brings about such disadvantage as a complicated manufacturing method and a higher cost. Further, the wire-bonding step for mounting each device on the package and establishing connection needs a preparatory step of rotating the whole package 90 degrees, which degrades work efficiency and reliability and causes a problem in terms of processing efficiency.
Further, in structuring an optical pickup apparatus with use of the prior art semiconductor laser apparatus, position adjustment such as optical axis adjustment is complicated by these problems.